Heating, ventilation, and/or air conditioning (HVAC) furnaces are widely used in commercial and residential environments for heating and otherwise conditioning interior spaces. Gas-fired furnaces are known to generate and emit oxides of nitrogen (NOX). NOX is a term used herein to describe the various oxides of nitrogen, in particular NO, N2O and NO2. NOX emissions from gas-fired furnaces are typically attributable to less than optimal air-fuel mixtures and combustion temperatures.